DIP or SMD for car projects

Hello everyone, I'm planning on making a CMOS based car alarm for a friends original mini. The brains will be stuck in a plastic box in the engine bay for space reasons, but there will probably be a fair amount of vibration. Would it be better to use Dips and sockets with a tie wrap/zip tie holding each chip in place, use dips directly soldered to the board or SMD devices for maximum reliability? I'll probably be using 60/40 lead solder as it's what I have in the house. Any pointers? Many thanks - Mike

SMD's can be done, but it has to be done right. Anyone can do dips

I use smd's on most of my auto projects, my third brake light has been going for over 4 years and sat in traffic jambs and sat in the parking lot for two weeks in Florida in July during a heat wave, and all the smd chips and leds didn't fall off (knock on wood) but I leave the windows cracked open a bit now, other items didn't fare at all good though.....

No sockets. 60/40 is fine for DIPS, but not SMT.

Stencils and paste is the right way. 63/37 solder might work in a pinch. In fact it does. My first SMD replacement was a CPU on a car radio. I used the tack the corners and solder upside down trick and it worked well.

You might want to consider a conformal coating.

For vibration the best would be SMD with a potting compound